“Did you exercise today?”
“No, I didn’t have time.”
When you ask a friend why he or she doesn’t exercise, that is the most common answer given. While some people use "lack of time" as an excuse, others want to exercise but really don’t have time.
To address this, many sport and exercise scientists recommend high-intensity interval training (HIT).
What is HIT?
HIT is an approach of exercising which involves short bursts of intense effort, interspersed with low-intensity recovery.
HIT is known for its efficient use of time. World Health Organization recommends adults aged 18 to 64 to carry out at least 150 minutes of moderate-intensity aerobic activity per week, but supporters of HIT highlight that similar benefits can be gained with much less time.
For example, if you don’t have time for a long, steady paced run, the HIT version would include a short intense sprint, then a slow recovery jog, then another short sprint, and another slow jog, with this combination repeated a few times.
However, many HIT versions are not much more time-efficient than traditional exercises. In fact, the time it takes to carry out some HIT versions are only slightly less than traditional exercises.
Besides, the high-intensity nature of HIT may lead to negative affective states — increasing feelings of discomfort or difficulty. This means that people are unlikely to stick to these exercises every day.
In order to deal with these issues, sports physiologist Richard Metcalfe has developed reduced exertion HIT (REHIT).
What is REHIT?
REHIT is a genuinely time efficient and more tolerable approach to exercise. It involves warm up and cool down, and two 20-second sprints, with this combination repeated for ten minutes.
Initial evidence suggests that REHIT can improve insulin sensitivity and heart and lung function without causing discomfort or difficulty.
Scientists believe that HIT or REHIT can be integrated into everyday life.
For example, you can climb stairs more quickly instead of climbing them regularly. A 2017 study even suggests that brief and intense stair climbing can improve cardiorespiratory fitness in untrained women.
Other day to day things such as tidying, cleaning the car, or gardening may also be performed more vigorously as a kind of HIT.
Although there is not enough evidence to suggest that HIT or REHIT can be adopted by everyone, doing some activities more vigorously can be a straightforward approach to getting fitter and healthier in the future.